FIG. 1 shows a schematic side view of a working vehicle 1 adapted for work on overhead power lines and which includes an air conditioning system 10 for a worker A.
Air conditioning system 10, illustrated in FIG. 2, includes an oil hydraulic motor 20, a generator 30 and a compressor 40, each of which is disposed in the lower portion of a case 101. The rotational force of oil hydraulic motor 20 is transmitted to generator 30 and compressor 40 through a belt 50. An upper passageway 60 is formed at the upper portion of case 101 and includes an evaporator 70 and a fan 80. A condenser 90 and a fan 100 for the condenser are also disposed in case 101. When the air conditioning system is turned on, generator 30 and compressor 40 are driven in response to the rotational force of oil hydraulic motor 20. Generator 30 generates and transmits electricity to fans 80 and 100, whereby fans 80 and 100 are driven. Refrigerant in a refrigerant circuit is circulated through evaporator 70 and condenser 90 by the operation of compressor 40. Accordingly, air which flows into upper passageway 60 is cooled by evaporator 70 and sent to the interior of a suit a of worker A through a flexible hose 110. Suit a is made of rubber to insulate the worker and protect him from electric shocks. The temperature of the cooled air is controlled by a thermo-amplifier 4 which is coupled to a temperature sensor 2 (disposed on the outflow side of evaporator 70), an electromagnetic clutch 3 which is mounted on compressor 40, and generator 30. This arrangement is schematically illustrated in FIG. 3.
In the above-described air conditioning system, electromotive force produced by generator 30 is used to drive fans 80 and 100, electromagnetic clutch 3 and thermo-amplifier 4. The use of electrical devices by a worker working in close proximity to power lines is dangerous and increases the chances that the worker will accidentally be injured or killed during the performance of his job. In addition, since fans 80 and 100 are driven by an electrical motor, the system is expensive to operate.
Furthermore, compressor 40 must be periodically stopped to remove frost on evaporator 70 in order to maintain the refrigerating capacity of the air conditioning system. This requires that the air conditioning operation be stopped during removal of the frost.